STORAGE DEVICES AND METHODS OF OPERATING STORAGE DEVICES

A storage device includes a nonvolatile memory device including a memory cell array and a storage controller to control the nonvolatile memory device. The memory cell array includes word-lines, memory cells and word-line cut regions dividing the word-lines into memory blocks. The storage controller includes an error correction code (ECC) engine including an ECC encoder and a memory interface. The ECC encoder performs a first ECC encoding operation on each of sub data units in user data to generate parity bits and generate a plurality of ECC sectors, selects outer cell bits to be stored in outer cells to constitute an outer ECC sector including the outer cell bits and performs a second ECC encoding operation on the outer ECC sector to generate outer parity bits. The memory interface transmits, to the nonvolatile memory device, a codeword set including the ECC sectors and the outer parity bits.